The present invention relates to linear magnetic recording tapes and corresponding tape drive heads, and more specifically to linear magnetic tape using a timing-based servo technology that has smaller width servo bands and shorter servo frame length.
Various data storage media and recording media such as magnetic tape, magnetic disks, optical tape, optical disks, holographic disks, holographic cards, and the like, allow for storage and retrieval of data. In particular, in magnetic media, data is typically stored as magnetic transitions, e.g., data is magnetically recorded on a surface of the media. The data stored is typically arranged in data tracks. A typical magnetic storage medium, such as a magnetic tape, typically includes several data tracks. Data tracks may be written and read individually, or sets of data tracks may be written and read in parallel. Optical media, holographic media and other media formats may also make use of such data tracks. Transducer (read/write) heads are positioned relative to the data tracks to read/write data along the tracks. Accordingly, a tape drive head locates each data track and accurately follows its path. To achieve this, servo techniques have been developed which allow for a precise positioning of the head relative to the data tracks. One such technique makes use of servo patterns, that is, patterns of signals or recorded marks on the medium, which are tracked by the head. The servo patterns are recorded on the recording medium such as to provide a position reference for the data tracks. In other words, a servo head reads a servo pattern, which is then interpreted by a servo controller into a position error signal (PES). The latter is then used to adjust the distance of the servo head relative to the servo pattern and thereby ensure a proper positioning of the transducers with respect to the set of data tracks.
In a magnetic tape medium, the servo patterns are stored on dedicated tracks (called servo bands). A plurality of patterns may be defined within a servo band and a plurality of servo bands might be relied upon, the data tracks being arranged between the servo bands. A particular servo technique is the time-based servo (TBS) pattern, which makes use of non-parallel marks, to which time or distance variables may be associated. The time/distance offset between the detection of a set of servo marks is translated into a position signal. A PES may then be generated by subtracting a reference signal from the position signal to determine the position of a transducer relative to a data track.